The invention in question refers to a device for applying labels. Its purpose is to provide greater speed in labelling, and to increase the efficiency of the marking line.
The purpose of the invention is furthermore to make the labelling without the applicator devices coming into contact with the surface of the product that is to be labelled, and to prevent the product from suffering any kind of damage in the labelling.
The invention can be applied to the labelling of food products, preferably fruit, but it can obviously be used in any kind of product that needs to be labelled.
A close state of the art to the invention in question is made up of the Patent of Invention P-9601222 whose owner is the same as the owner of the present invention, and it describes a device that will allow the automatic sticking of labels that are adhered on a longitudinal strip of waxed paper that determines a roll and that furthermore counts on a motor that performs the unwinding of the waxed paper. This waxed paper runs across a circuit that includes a guide-wedge making it possible for the waxed paper to change direction brusquely causing the labels to be detached from it. The labels are thus left in a condition to be adhered to the surface to be marked by means of a dual effect cylinder that is finished off at the bottom by an applicator whose surface in contact with the label is slightly concave. The label is retained on this cylinder by effect of the traction produced by the static electricity on the labels when rubbing against the rollers, after separating the labels. All of this is performed so that by means of a photocell, the pass of the product to be marked is detected, activating the dual effect cylinder until the applicator comes in contact with the surface to be marked on which the label is stuck.
This type of device presents the inconvenience that the speed of marking is limited by the label application device, and also this needs to be in contact with the product to be marked, such that the surface could suffer damage. This is more likely to occur in the labelling of food products.
In order to avoid any contact between the label application device and the product to be marked, EP-A-0908390 and U.S. Pat. No. 5,885,406 disclose a device for applying labels comprising an applicator surface provided with a plurality of openings through which a suction is established to retain the label (once detached from the label strip) and through which pressurized air is delivered to propel the label towards an article to be marked.
The invention has developed a new device for applying labels that embodies a roll of tape to which a plurality of labels are adhered, that are aligned longitudinally. The invention furthermore has means that cause the label to become detached from the tape, and it has means for applying the labels on the product to be marked. The tape is unwound by a motor that activates drive rollers and a tape winding recovery roller after the labels are detached. It is characterized in that the means for applying the label are made up of suction means of the detached label, by retention means of that detached label, and by blowing means of the retained label, so that these blowing means energetically project the label over the surface of the product to be marked on which it is stuck without there being contact between the application means of the label and the labelled product, which represents a big advantage. This advantage is more desirable when it is obtained in the case when the surface of the product to be marked does not have a certain degree of solidity, as occurs with products such as fruit, or food products in general.
The means for withholding the detached label include a head through which the suction is applied to retain the sticker, and through which the blowing is also applied on the retained sticker to make it stick on the surface of the product.
In a preferable execution, the head has a homogeneously multiperforated surface, through the perforations of which the suction and blowing air flows, so that the air flow is broken down into numerous push and absorption points, that are evidently distributed homogeneously, making a correct absorption of the label, and it also has an absolutely flat projection.
Another characteristic of the invention lies in the fact that a pneumatic distributor has been foreseen that is controlled electronically to govern the suction function and the projection function of the label.
The suction means include a suction circuit that is connected to the head and to the pneumatic distributor.
In addition, the blowing means have a fast release valve, that feeds the head, and whose operation is controlled by the pneumatic distributor.
The blowing means also have a pressure accumulator that is connected to the fast release valve to provide additional pressure to the head and to impel the label with suitable force against the surface of the product to be marked.
The invention device is fitted on a support that can be regulated according to shafts X and Y to facilitate the labelling of a plurality of food products that occupy a certain surface, so that a wider area can be labelled, for example a box of fruit.
To facilitate a better understanding of this description and forming an integral part of it, a number of figures are included that represent the purpose of the invention by an illustrative and non-restrictive way.